package com.sdb.demo_2;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    private Button btnStartB;
    private long lastPressTime = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        btnStartB = findViewById(R.id.btn_start_B);
        btnStartB.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent();
                intent.setClass(MainActivity.this,ActivityB.class);
                startActivity(intent);
            }
        });
    }

    @Override
    public void onBackPressed() {
        long currentPressTime = System.currentTimeMillis();

        if (currentPressTime - lastPressTime > 2000){
            lastPressTime = currentPressTime;
            Toast.makeText(MainActivity.this,"再按一次退出",Toast.LENGTH_SHORT).show();
        }
        else {
            super.onBackPressed();
        }
    }
}
